This invention relates to a storage installation for the storage of liquefied gas, and particularly liquefied natural gas.
More particularly, the invention relates to such a storage installation comprising a storage vessel surrounded by a wall or dam in such a manner that a collecting space is formed around the vessel. The main object of this collecting space is, in the event of damage to the tank or lines, to prevent the contents of the vessel from flowing away, by containing leaking liquefied gas in the said collecting space. This reduces the danger, of for example fire, to adjacent vessel or installations or to persons present in the vicinity.
A relatively important source of danger remains, however, in the event of leakage of liquefied gas caused by damage to vessel or lines. When the cold liquefied gas flows into the collecting space, it will suddenly absorb a large quantity of heat from the environment, thus causing the escaping liquefied gas to evaporate very rapidly. As a result a very large, concentrated cloud of gas could be formed very suddenly. This large, very rapidly forming inflammable cloud of gas increases the danger, of for example explosion or fire, even at a relatively large distance from the tank.
In addition to the quantity of liquefied gas flowing into the collecting space, the major factors determining the rate of formation, size and concentration of the gas cloud are the quantity of heat present in the vicinity which can flow to the liquefied gas and the rate at which heat can flow.
An important source of available heat is the ground of the collecting space and the wall or dam surrounding the collecting space.